Table 1.

Characteristics of included studies

Paper	Country	Design	Description and aims	Population	Care recipient characteristics	Caregiver characteristics
Aggar 2012* [25]	Australia	Cross-sectional	Questionnaire-based longitudinal study. Aim was to compare caregiver reaction, depression, and anxiety in primary family caregivers of older adults enrolled in the control and intervention arms of a trial of an intervention targeting frailty. Timepoints were 3, 6, 9, 12, and 15 months after initiation of the trial.	119 primary informal caregivers of older adults recently discharged from an aged care or rehabilitation service, residing in a major metropolitan area, and participating in a randomized trial targeting frailty. All recipients were frail (FFS ≥3).	Mean age: 84.4±6.0 Female: 71% MMSE>18** Frail; 64.7% Very frail; 35.3%	Mean age; 66.7 ± 13.7 Female; 59.7% Co-residing with CR; 57.1% Self-reported good health; 76% Provide <20 (>40) h/week of care; 52.1%
Comans 2011 [27]	Australia	Cross-sectional	Cross-sectional analysis of baseline characteristics of an older population enrolled in an RCT of community rehabilitation service delivery models. Aim was to identify factors contributing to reduced quality of life and increased caregiver strain (CSI).	107 older adults participating in an RCT of community rehabilitation service delivery models. Participants eligible if referred to a community rehabilitation service for falls or functional decline, ambulatory, nonresident in high-level care, and not unable to participate in a rehabilitation program due to physical or cognitive function. 45 participants had a caregiver who completed a CSI.	Mean age; 78.93 ± 7.67 Female gender; 66% EQ-5D; 0.56 ± 0.31 (reported normative value 0.7) EQ-VAS; 61.76 ± 15.62 (reported normative value 68) FAI; 19.43 ± 8.81 (reported normative value 40.86) AMTS; 8.68 ± 1.19 (reported normative value 8–10) TUG; 20.57 s ± 14.23 s (reported normative value <10) Caregiver available; 42%	(NB; only 42% of participants had caregiver available) Mean CSI; 4.4 ± 3.53
Cullen 1997 [28]	Australia	Australia Cross-sectional	Cross-sectional analysis of population of cognitively impaired older adults drawn from a longitudinal study and their CGs. Aim was to examine associations between CR sociodemographic, caregiver and relationship characteristics with caregiver morbidity singly and after controlling for clinical characteristics of the CRs.	90 dyads consisting of community dwelling older adults with mild or greater levels of cognitive impairment (MMSE <27) and their informal CGs.	Mean age; 79 ± 6 Female gender; 54% Mean MMSE; 23.4 ± 3.6 Married; 54.4%	Mean age; 61 ± 14 Female gender; 81% Spouse of CR; 44% Child/inlaw of CR; 45.6%
Faes 2011 [29]	Netherlands	Randomized controlled trial	RCT of a multifactorial fall prevention program. Aim was to assess whether intervention (program) was more effective than usual geriatric care in preventing falls in frail communitydwelling older fallers, with and without cognitive impairment, and in alleviating subjective caregiver burden in subjects’ CGs.	33 dyads consisting of community dwelling older adults who had fallen at least once in the last 6 months and who met at least 2 of the FFS criteria, and their informal caregivers.	No sociodemographic characteristics (e.g., age) reported. All CRs able to walk at least 15 m independently with or without walking aid. All CRs had life expectancy >12 months. All CRs had MMSE >15.	Mean age (intervention/control); 67.3 ± 13.1/64.3 ± 14.3 Female gender (intervention/control); 50/67% Living with CR (intervention/control); 55/47% Baseline ZBI (intervention/control); 5.2/6.0 Total caregiving hours per week (intervention/control); 8.0/10.5
Kim 2008 [30]	USA	Cross-sectional	Tele-survey-based study comparing caregiving burden and distress, among CGs of 4 types of CRs: cancer, diabetes, dementia, frail older adults.	606 CGs across all 4 groups, including 135 caregivers (“frail elderly” group) of CRs whom their CG described as “frail due to age.”	(“Frail elderly” group only) Mean age; 81.69 ± 9.77	(“Frail elderly” group only) Mean age; 46.23 ± 14.99 Female gender; 47.4% Relationship to CR; Spouse/partner; 0.7% Child/in-law; 50.4% Sibling/in-law; 1.5% Grandchild/in-law; 18.5% Friend/neighbor/nonrelative; 17.8% Other; 11.1%

*This publication represents the index study for a series of five papers by a single set of investigators [22–26]. An explanation of the relationship between these articles appears in the “Results” section of the manuscript

** Care recipient demographics were not reported in this paper [25]; these details were extracted from Aggar 2011b, which involves the same population [24].